// SPDX-License-Identifier: GPL-2.0
#include <test_progs.h>
#include <linux/genetlink.h>
#include "network_helpers.h"
#include "bpf_smc.skel.h"

#ifndef IPPROTO_SMC
#define IPPROTO_SMC 256
#endif

#define CLIENT_IP			"127.0.0.1"
#define SERVER_IP			"127.0.1.0"
#define SERVER_IP_VIA_RISK_PATH	"127.0.2.0"

#define SERVICE_1	80
#define SERVICE_2	443
#define SERVICE_3	8443

#define TEST_NS	"bpf_smc_netns"

static struct netns_obj *test_netns;

struct smc_policy_ip_key {
	__u32  sip;
	__u32  dip;
};

struct smc_policy_ip_value {
	__u8	mode;
};

#if defined(__s390x__)
/* s390x has default seid  */
static bool setup_ueid(void) { return true; }
static void cleanup_ueid(void) {}
#else
enum {
	SMC_NETLINK_ADD_UEID = 10,
	SMC_NETLINK_REMOVE_UEID
};

enum {
	SMC_NLA_EID_TABLE_UNSPEC,
	SMC_NLA_EID_TABLE_ENTRY,    /* string */
};

struct msgtemplate {
	struct nlmsghdr n;
	struct genlmsghdr g;
	char buf[1024];
};

#define GENLMSG_DATA(glh)	((void *)(NLMSG_DATA(glh) + GENL_HDRLEN))
#define GENLMSG_PAYLOAD(glh)	(NLMSG_PAYLOAD(glh, 0) - GENL_HDRLEN)
#define NLA_DATA(na)		((void *)((char *)(na) + NLA_HDRLEN))
#define NLA_PAYLOAD(len)	((len) - NLA_HDRLEN)

#define SMC_GENL_FAMILY_NAME	"SMC_GEN_NETLINK"
#define SMC_BPFTEST_UEID	"SMC-BPFTEST-UEID"

static uint16_t smc_nl_family_id = -1;

static int send_cmd(int fd, __u16 nlmsg_type, __u32 nlmsg_pid,
		    __u16 nlmsg_flags, __u8 genl_cmd, __u16 nla_type,
		    void *nla_data, int nla_len)
{
	struct nlattr *na;
	struct sockaddr_nl nladdr;
	int r, buflen;
	char *buf;

	struct msgtemplate msg = {0};

	msg.n.nlmsg_len = NLMSG_LENGTH(GENL_HDRLEN);
	msg.n.nlmsg_type = nlmsg_type;
	msg.n.nlmsg_flags = nlmsg_flags;
	msg.n.nlmsg_seq = 0;
	msg.n.nlmsg_pid = nlmsg_pid;
	msg.g.cmd = genl_cmd;
	msg.g.version = 1;
	na = (struct nlattr *)GENLMSG_DATA(&msg);
	na->nla_type = nla_type;
	na->nla_len = nla_len + 1 + NLA_HDRLEN;
	memcpy(NLA_DATA(na), nla_data, nla_len);
	msg.n.nlmsg_len += NLMSG_ALIGN(na->nla_len);

	buf = (char *)&msg;
	buflen = msg.n.nlmsg_len;
	memset(&nladdr, 0, sizeof(nladdr));
	nladdr.nl_family = AF_NETLINK;

	while ((r = sendto(fd, buf, buflen, 0, (struct sockaddr *)&nladdr,
			   sizeof(nladdr))) < buflen) {
		if (r > 0) {
			buf += r;
			buflen -= r;
		} else if (errno != EAGAIN) {
			return -1;
		}
	}
	return 0;
}

static bool get_smc_nl_family_id(void)
{
	struct sockaddr_nl nl_src;
	struct msgtemplate msg;
	struct nlattr *nl;
	int fd, ret;
	pid_t pid;

	fd = socket(AF_NETLINK, SOCK_RAW, NETLINK_GENERIC);
	if (!ASSERT_OK_FD(fd, "nl_family socket"))
		return false;

	pid = getpid();

	memset(&nl_src, 0, sizeof(nl_src));
	nl_src.nl_family = AF_NETLINK;
	nl_src.nl_pid = pid;

	ret = bind(fd, (struct sockaddr *)&nl_src, sizeof(nl_src));
	if (!ASSERT_OK(ret, "nl_family bind"))
		goto fail;

	ret = send_cmd(fd, GENL_ID_CTRL, pid,
		       NLM_F_REQUEST, CTRL_CMD_GETFAMILY,
		       CTRL_ATTR_FAMILY_NAME, (void *)SMC_GENL_FAMILY_NAME,
		       strlen(SMC_GENL_FAMILY_NAME));
	if (!ASSERT_OK(ret, "nl_family query"))
		goto fail;

	ret = recv(fd, &msg, sizeof(msg), 0);
	if (msg.n.nlmsg_type == NLMSG_ERROR)
		goto fail;
	if (!ASSERT_FALSE(ret < 0 || !NLMSG_OK(&msg.n, ret),
			  "nl_family response"))
		goto fail;

	nl = (struct nlattr *)GENLMSG_DATA(&msg);
	nl = (struct nlattr *)((char *)nl + NLA_ALIGN(nl->nla_len));
	if (!ASSERT_EQ(nl->nla_type, CTRL_ATTR_FAMILY_ID, "nl_family nla type"))
		goto fail;

	smc_nl_family_id = *(uint16_t *)NLA_DATA(nl);
	close(fd);
	return true;
fail:
	close(fd);
	return false;
}

static bool smc_ueid(int op)
{
	struct sockaddr_nl nl_src;
	struct msgtemplate msg;
	struct nlmsgerr *err;
	char test_ueid[32];
	int fd, ret;
	pid_t pid;

	/* UEID required */
	memset(test_ueid, '\x20', sizeof(test_ueid));
	memcpy(test_ueid, SMC_BPFTEST_UEID, strlen(SMC_BPFTEST_UEID));
	fd = socket(AF_NETLINK, SOCK_RAW, NETLINK_GENERIC);
	if (!ASSERT_OK_FD(fd, "ueid socket"))
		return false;

	pid = getpid();
	memset(&nl_src, 0, sizeof(nl_src));
	nl_src.nl_family = AF_NETLINK;
	nl_src.nl_pid = pid;

	ret = bind(fd, (struct sockaddr *)&nl_src, sizeof(nl_src));
	if (!ASSERT_OK(ret, "ueid bind"))
		goto fail;

	ret = send_cmd(fd, smc_nl_family_id, pid,
		       NLM_F_REQUEST | NLM_F_ACK, op, SMC_NLA_EID_TABLE_ENTRY,
		       (void *)test_ueid, sizeof(test_ueid));
	if (!ASSERT_OK(ret, "ueid cmd"))
		goto fail;

	ret = recv(fd, &msg, sizeof(msg), 0);
	if (!ASSERT_FALSE(ret < 0 ||
			  !NLMSG_OK(&msg.n, ret), "ueid response"))
		goto fail;

	if (msg.n.nlmsg_type == NLMSG_ERROR) {
		err = NLMSG_DATA(&msg);
		switch (op) {
		case SMC_NETLINK_REMOVE_UEID:
			if (!ASSERT_FALSE((err->error && err->error != -ENOENT),
					  "ueid remove"))
				goto fail;
			break;
		case SMC_NETLINK_ADD_UEID:
			if (!ASSERT_OK(err->error, "ueid add"))
				goto fail;
			break;
		default:
			break;
		}
	}
	close(fd);
	return true;
fail:
	close(fd);
	return false;
}

static bool setup_ueid(void)
{
	/* get smc nl id */
	if (!get_smc_nl_family_id())
		return false;
	/* clear old ueid for bpftest */
	smc_ueid(SMC_NETLINK_REMOVE_UEID);
	/* smc-loopback required ueid */
	return smc_ueid(SMC_NETLINK_ADD_UEID);
}

static void cleanup_ueid(void)
{
	smc_ueid(SMC_NETLINK_REMOVE_UEID);
}
#endif /* __s390x__ */

static bool setup_netns(void)
{
	test_netns = netns_new(TEST_NS, true);
	if (!ASSERT_OK_PTR(test_netns, "open net namespace"))
		goto fail_netns;

	SYS(fail_ip, "ip addr add 127.0.1.0/8 dev lo");
	SYS(fail_ip, "ip addr add 127.0.2.0/8 dev lo");

	return true;
fail_ip:
	netns_free(test_netns);
fail_netns:
	return false;
}

static void cleanup_netns(void)
{
	netns_free(test_netns);
}

static bool setup_smc(void)
{
	if (!setup_ueid())
		return false;

	if (!setup_netns())
		goto fail_netns;

	return true;
fail_netns:
	cleanup_ueid();
	return false;
}

static int set_client_addr_cb(int fd, void *opts)
{
	const char *src = (const char *)opts;
	struct sockaddr_in localaddr;

	localaddr.sin_family = AF_INET;
	localaddr.sin_port = htons(0);
	localaddr.sin_addr.s_addr = inet_addr(src);
	return !ASSERT_OK(bind(fd, &localaddr, sizeof(localaddr)), "client bind");
}

static void run_link(const char *src, const char *dst, int port)
{
	struct network_helper_opts opts = {0};
	int server, client;

	server = start_server_str(AF_INET, SOCK_STREAM, dst, port, NULL);
	if (!ASSERT_OK_FD(server, "start service_1"))
		return;

	opts.proto = IPPROTO_TCP;
	opts.post_socket_cb = set_client_addr_cb;
	opts.cb_opts = (void *)src;

	client = connect_to_fd_opts(server, &opts);
	if (!ASSERT_OK_FD(client, "start connect"))
		goto fail_client;

	close(client);
fail_client:
	close(server);
}

static void block_link(int map_fd, const char *src, const char *dst)
{
	struct smc_policy_ip_value val = { .mode = /* block */ 0 };
	struct smc_policy_ip_key key = {
		.sip = inet_addr(src),
		.dip = inet_addr(dst),
	};

	bpf_map_update_elem(map_fd, &key, &val, BPF_ANY);
}

/*
 * This test describes a real-life service topology as follows:
 *
 *                             +-------------> service_1
 *            link 1           |                     |
 *   +--------------------> server                   |  link 2
 *   |                         |                     V
 *   |                         +-------------> service_2
 *   |        link 3
 *  client -------------------> server_via_unsafe_path -> service_3
 *
 * Among them,
 * 1. link-1 is very suitable for using SMC.
 * 2. link-2 is not suitable for using SMC, because the mode of this link is
 *    kind of short-link services.
 * 3. link-3 is also not suitable for using SMC, because the RDMA link is
 *    unavailable and needs to go through a long timeout before it can fallback
 *    to TCP.
 * To achieve this goal, we use a customized SMC ip strategy via smc_hs_ctrl.
 */
static void test_topo(void)
{
	struct bpf_smc *skel;
	int rc, map_fd;

	skel = bpf_smc__open_and_load();
	if (!ASSERT_OK_PTR(skel, "bpf_smc__open_and_load"))
		return;

	rc = bpf_smc__attach(skel);
	if (!ASSERT_OK(rc, "bpf_smc__attach"))
		goto fail;

	map_fd = bpf_map__fd(skel->maps.smc_policy_ip);
	if (!ASSERT_OK_FD(map_fd, "bpf_map__fd"))
		goto fail;

	/* Mock the process of transparent replacement, since we will modify
	 * protocol to ipproto_smc accropding to it via
	 * fmod_ret/update_socket_protocol.
	 */
	write_sysctl("/proc/sys/net/smc/hs_ctrl", "linkcheck");

	/* Configure ip strat */
	block_link(map_fd, CLIENT_IP, SERVER_IP_VIA_RISK_PATH);
	block_link(map_fd, SERVER_IP, SERVER_IP);

	/* should go with smc */
	run_link(CLIENT_IP, SERVER_IP, SERVICE_1);
	/* should go with smc fallback */
	run_link(SERVER_IP, SERVER_IP, SERVICE_2);

	ASSERT_EQ(skel->bss->smc_cnt, 2, "smc count");
	ASSERT_EQ(skel->bss->fallback_cnt, 1, "fallback count");

	/* should go with smc */
	run_link(CLIENT_IP, SERVER_IP, SERVICE_2);

	ASSERT_EQ(skel->bss->smc_cnt, 3, "smc count");
	ASSERT_EQ(skel->bss->fallback_cnt, 1, "fallback count");

	/* should go with smc fallback */
	run_link(CLIENT_IP, SERVER_IP_VIA_RISK_PATH, SERVICE_3);

	ASSERT_EQ(skel->bss->smc_cnt, 4, "smc count");
	ASSERT_EQ(skel->bss->fallback_cnt, 2, "fallback count");

fail:
	bpf_smc__destroy(skel);
}

void test_bpf_smc(void)
{
	if (!setup_smc()) {
		printf("setup for smc test failed, test SKIP:\n");
		test__skip();
		return;
	}

	if (test__start_subtest("topo"))
		test_topo();

	cleanup_ueid();
	cleanup_netns();
}
